There's a post "Interim Windows Vista Build 5728 Released Today" over on the Vista team blog. I've already explained that "true" builds of vista move in increments of 16, so this is 8 builds on from 5600 which is RC-1 (which I've only been using for 7 working days) .
I was expecting to see a release candiate 2 about a month after RC-1 - still a week or two away - with the release to manufacturing a month after that. I don't know if this is a substiute for RC2 or if the intervals are going to be a little longer, putting RTM in mid November rather than early November. If I get any more information I'll share it when I have it.
Bonus link: Also on the Vista team blog, they've mapped where our beta testers are. Awesome use of MapPoint.